World History, the Social Sciences, and the Dynamics of Contemporary Global Politics

This article argues that the discipline of world history, with its interdisciplinary ties to the social sciences and its incorporation of the cultural insights of recent historiography, makes an ideal tool for conveying the complexities of the contemporary world in a “user-friendly” way. It argues further that one particular global structural analysis, from the author’s world history textbook Frameworks of World History, exposes a deep pattern that helps explain many of the central conflicts in contemporary global politics. By highlighting the tension that has existed between individual communities, or hierarchies, and the networks that connected those communities, a tension going back as far as the modern human species, the article exposes the deep roots of the central conflict between today’s global network and its cultural value of capitalism on the one hand, and modern hierarchies and their central value of nationalism on the other. The cultural aspect of this analysis offers a possible route forward from the problems and repressive politics that flow from this central conflict

Unidimensional model of the ad-atom diffusion on a substrate submitted to a standing acoustic wave II. Solutions of the ad-atom motion equation

The ad-atom dynamic equation, a Langevin type equation is analyzed and solved using some non-linear analytical and numerical tools. We noticeably show that the effect of the surface acoustic wave is to induce an effective potential that governs the diffusion of the ad-atom: the minima of this effective potential correspond to the preferential sites in which the ad-atom spends more time. The strength of this effective potential is compared to the destructuring role of the thermal diffusion and to the crystalline potential induced by the substrate

Density functional study of copper segregation in aluminum

The structural and electronic properties of Cu segregation in aluminum are studied in the framework of the density functional theory, within the projector augmented plane-wave method and both its local density approximation (LDA) and generalized gradient approximation (GGA). We first studied Al–Cu interactions in bulk phase at low copper concentration (≤3.12%: at). We conclude to a tendency to the formation of a solid solution at T=0 K. We moreover investigated surface alloy properties for varying compositions of a Cu doped Al layer in the (111) Al surface then buried in an (111) Al slab. Calculated segregation energies show unstable systems when Cu atoms are in the surface position (position 1). In the absence of ordering effects for Cu atoms in a layer (xCu=1/9 and xCu=1/3), the system is more stable when the doped layer is buried one layer under the surface (position 2), whereas for xCu=1/2 to xCu=1 (full monolayer), the doped layer is more accommodated when buried in the sub-sub-surface (position 3). First stage formation of GP1- and GP2-zones was finally modeled by doping (100) Al layers with Cu clusters in a (111) Al slab, in the surface then buried one and two layers under the surface. These multilayer clusters are more stable when buried one layer beneath the surface. Systems modeling GP1-zones are more stable than systems modeling GP2-zones. However the segregation of a full copper (100) monolayer in an (100) Al matrix shows a copper segregation deep in the bulk with a segregation barrier. Our results fit clearly into a picture of energetics and geometrical properties dominated by preferential tendency to Cu clustering close to the (111) Al surface

Statistics of work and fluctuation theorems for microcanonical initial states

The work performed on a system in a microcanonical state by changes in a control parameter is characterized in terms of its statistics. The transition probabilities between eigenstates of the system Hamiltonians at the beginning and the end of the parameter change obey a detailed balance-like relation from which various forms of the microcanonical fluctuation theorem are obtained. As an example, sudden deformations of a two dimensional harmonic oscillator potential are considered and the validity of the microcanonical Jarzynski equality connecting the degrees of degeneracy of energy eigenvalues before and after the control parameter change is confirmed.Comment: 16 pages, 5 figure